Cascade reactions of Me3Si-Substituted imidazolidine-1,3-diols with PbO2, including oxidation of the corresponding diol and subsequent elimination of the trimethylsilyl fragment

Cascade reactions of Me3Si-Substituted imidazolidine-1,3-diols with PbO2, including oxidation of the corresponding diol and subsequent elimination of the trimethylsilyl fragment Full article

Journal

European Journal of Organic Chemistry
ISSN: 1434-193X , E-ISSN: 1099-0690

Output data

Year: 2007, Volume: 2007, Number: 22, Pages: 3639-3647 Pages count : 9 DOI: 10.1002/ejoc.200700113

Tags

nitrogen oxides; cleavage reactions; oxidation; protecting groups; alkynes

Authors

Tretyakov Eugene , Romanenko Galina , Ikorskii Vladimir , Stass Dmitry , Vasiliev Vladimir , Demina Maria , Mareev Alexander , Medvedeva Alevtina , Gorelik Elena , Ovcharenko Victor

Affiliations

1	(Данные Web of science) Russian Acad Sci, Inst Chem Kinet & Combust, Novosibirsk 630090, Russia
2	(Данные Web of science) Russian Acad Sci, Int Tomog Ctr, Siberian Branch, Novosibirsk 630090, Russia
3	(Данные Web of science) Russian Acad Sci, NN Vorozhtsov Inst Organ Chem, Siberian Branch, Novosibirsk 630090, Russia
4	(Данные Web of science) Russian Acad Sci, Siberian Branch, AE Favorsky Irkutsk Inst Chem, Irkutsk 664033, Russia

was found that reactions of 2-Me3Si-R-substituted (Si-C-sp or Si-C-sp(2)) imidazolidine-1,3-diols with PbO2 in MeOH are cascade reactions, which involve the oxidation of imidazolidine-1,3-diols into nitronyl nitroxide (NN-R-SiMe3) and further elimination of the Me3Si group to give NN-R-H. The efficiency of a one-pot approach in the synthesis of nitronyl nitroxides is demonstrated by reference to syntheses of 2-ethynyl-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (2), 2-(4-ethynylphenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (8), (E)-4,4,5,5-tetramethyl-2-[2-(pyrrolidin-1-yl)vinyl]-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (3a), (E)-2-[2-(diisopropylamino)vinyl]-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (3b), and 4,4,5,5-tetramethyl-2-(1H-1,2,3-triazol-5-yl)-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (H11). Interaction of 2 with secondary amines formed only trans isomers 3a and 3b. X-ray investigation of 3a and 3b confirmed that the reaction is regiospecific. Static magnetochemical measurements detected weak exchange interactions between the odd electrons of the paramagnetic centers in the solid nitronyl nitroxide products, including H11 whose crystals consist of helices formed by numerous intermolecular H bonds. The ESR spectra of 3a, 3b, and H11 show substantial delocalization of spin density to the substituent. Modeling reproducibly gave equal hyperfine coupling constants (HFC) for the imidazoline nitrogen atoms of 3b and different HFC for the nitrogen atoms of 3a and H11, indicating that rotation of the two cyclic substituents is hindered. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).

Tretyakov E. , Romanenko G. , Ikorskii V. , Stass D. , Vasiliev V. , Demina M. , Mareev A. , Medvedeva A. , Gorelik E. , Ovcharenko V.
Cascade reactions of Me3Si-Substituted imidazolidine-1,3-diols with PbO2, including oxidation of the corresponding diol and subsequent elimination of the trimethylsilyl fragment
European Journal of Organic Chemistry. 2007. V.2007. N22. P.3639-3647. DOI: 10.1002/ejoc.200700113 WOS Scopus РИНЦ

Published print:

Aug 1, 2007

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